The present invention relates to a wiring method and a wiring apparatus, and more particularly, to a wiring method and a wiring apparatus capable of easily forming a coil on an insulating substrate and easily laying a wire conductor on a circuit board or circuit substrate. The present invention also relates to an IC card manufacturing method capable of easily manufacturing an IC card provided with a chip module and/or an antenna coil, using the wiring method and/or wiring apparatus of the above kind.
Recently, the demand to reduce the heights of various components installed in an electric apparatus has been increasing. To meet such a demand, a coil serving as a transformer, a filter or the like may be configured in the form of a so-called xe2x80x9cplanar coilxe2x80x9d. The planar coil of this type is conventionally manufactured by subjecting a conductive plate or film to etching or mechanical punching or by winding an enameled wire two-dimensionally. However, there are many problems that hinder manufacturing a planar coil of desired properties at low cost and with high yield.
For example, according to the technique disclosed in Japanese Patent Preliminary Publication No. 57-136393, a wire conductor is laid in a desired pattern on an insulating substrate by moving a wiring head along the insulating substrate, wherein the wire conductor heated in advance using ultrasonic vibration is drawn out from the wiring head and embedded in an adhesive layer provided on a surface of the insulating substrate. This technique, however, needs an expensive ultrasonic vibration machine for heating the wire conductor just before it is laid on the substrate. This makes a wiring apparatus complicated in construction and high in cost. Further, controlling the wire temperature is very difficult. If the wire temperature varies, a uniform adhesion of the wire conductor to the adhesive layer cannot be attained, causing an incorrect conductor pattern.
According to the technique disclosed in Japanese Patent Preliminary Publication No. 8-294213, a patterned wire conductor placed on an insulating sheet is heated and pressed by a plate-shaped heating unit, to be embedded in the insulating sheet. This technique helps manufacture the planar coil relatively easily, but needs a heating unit large enough to cover the entirety of the patterned wire conductor. Further, even with such a large heating unit, it is difficult to heat the entirety of the patterned wire conductor uniformly at a time. If the patterned wire conductor is not heated uniformly, the wire conductor cannot be uniformly embedded in the insulating sheet, and, for example, part of the wire conductor rises from the insulating sheet. This may cause deformation and/or breakage of the patterned wire conductor.
Recently, an IC card having an information-processing function has come into widespread use. Particularly, an IC card accommodating therein an antenna coil for wireless communication with an external information processing apparatus is attracting attention. An antenna coil of the IC card of this type is formed on a card substrate and covered with a protective layers. Generally, the antenna coil is formed by etching a copper-foiled card substrate. However, this method requires a complicated process for making an antenna coil, and makes it difficult to form an antenna coil composed of coil parts or coil sections arranged at a sufficiently high density, because adjacent coil parts can be short-circuited if the spacing therebetween is small. The coil parts each have a circular or rectangular shape and arranged as a whole in a spiral form to constitute the antenna coil. Thus, the antenna coil formed by etching is not satisfactory in respect of antenna characteristics and manufacturing cost.
Alternatively, an antenna coil may be formed by plating or printing. With these techniques, however, it is generally difficult to provide an antenna coil with a thick conductor, posing problems in respect of the bending strength and tensile strength of the antenna coil, as well as the strength and reliability of the antenna coil mounted to an IC card.
As for the production of an antenna coil, it is known to soften a card substrate by hot air and embed a wire conductor into a surface portion of the softened card substrate, or to heat a wire conductor in advance with frictional heat generated by ultrasonic vibration and embed the heated wire conductor into a surface portion of a card substrate. However, these methods require severe control of hot air temperature and conductor heating temperature, respectively. When ultrasonic vibration is used, an expensive ultrasonic vibrator is required, which causes an increased equipment cost and fatigue breakage of a wire conductor attributable to ultrasonic vibration.
An object of the present invention is to provide a wiring method and a wiring apparatus capable of laying a wire conductor easily and precisely in the process of manufacturing a planar transformer, a circuit board, or the like.
Another object of the present invention is to provide an IC card manufacturing method capable of manufacturing an IC card provided with a chip module or an antenna coil, with ease and high reliability and at low cost, using the wiring method and wiring apparatus mentioned above.
In order to attain the above object, according to one aspect of the present invention, there is provided a wiring method comprising the steps of (a) forming an adhesive layer on a surface of a substrate, and (b) sticking a wire conductor on the surface of the substrate by causing a three-dimensional relative movement between the substrate and a wiring head adapted to guide the wire conductor such that the wiring head relatively moves along the adhesive layer formed on the surface of the substrate and the wiring head and the adhesive layer intermittently come close to each other for point contact.
In the wiring method of this invention, during the three-dimensional relative movement between the wiring head and the substrate, the wiring head intermittently comes close to the adhesive layer formed on the surface of the substrate for point contact therewith, so that the wire conductor supplied to and guided by the wiring head may be pressed between the wiring head and the adhesive layer formed on the substrate surface, to be stuck at a point on the substrate surface. Thus, the wire conductor is stuck on the substrate surface, point by point (point to point), securely and uniformly, like a thread fastened stitch by stitch by a sewing machine. The wire conductor is easily laid with high sticking strength and with uniformity only by relatively moving the wiring head and the substrate in three dimensions, so that the possibility of the wire conductor being deformed or broken after it is laid on the substrate may be reduced. As the adhesive layer, an adhesive layer having adhesiveness in an ordinary temperature or a pressure sensitive adhesive layer exhibiting adhesiveness when a pressure is applied by the wiring head is desirable. In the present invention, the wire conductor does not need to be heated before it is laid, making it possible to avoid increased cost due to the provision of heating means, severe control of heating temperature for the wire conductor, and unevenness in sticking the wire conductor on the substrate caused by unsuitable control of heating temperature. Further, the wiring method of this invention has little restriction about the kind of wire conductor and the pattern of relative movement between the wiring head and the substrate, which pattern closely relates to the wiring pattern. Therefore, a desired wire conductor can be laid in a desired wiring pattern, thereby making it possible to manufacture a planar transformer of desired properties, for instance.
Desirably, the three-dimensional relative movement between the wiring head and the substrate executed in the step (b) includes a relative translational motion between the wiring head and the substrate which is performed along the adhesive layer, and a relative reciprocal motion between the wiring head and the substrate which is performed in a direction of thickness of the substrate.
With this desirable method, the three-dimensional relative movement is carried out as a combination of the relative translational motion (two-dimensional relative motion) and the relative reciprocal motion which can be executed independently of each other. Therefore, the three-dimensional relative movement can be made with use of a relatively simple wiring apparatus and under a relatively simple control process. The relative translational motion can be made without interruption. For the relative translational motion, the movement of the wiring head and/or the substrate is controlled, for example, by a route control technique or a point-to-point control technique.
Desirably, the relative translational motion between the wiring head and the substrate is executed in association with the relative reciprocal motion therebetween.
The wire conductor to be laid on the surface of the substrate is comprised of a series of wire conductor sections which are continuous with one another. Each wire conductor section can be defined, for example, as corresponding to that part of the wire conductor which is drawn out from the wiring head in one cycle of the relative reciprocal motion. The relative reciprocal motion consists of a receding motion from a close position in which the wiring head and the adhesive layer are close to each other for point contact to a distant position in which the wiring head and the adhesive layer are most distant from each other, and an approaching motion from the distant position to the close position. The relative reciprocal motion is executed for each wire conductor section. The relative translational motion can be defined as being comprised of a series of relative translational motions performed for the series of wire conductor sections. The relative translational motion for each wire conductor section is carried out in association with the relative reciprocal motion. For example, it is preferable that the relative translational motion for each wire conductor section starts when the receding motion starts, and ends when the approaching motion ends.
In this desirable method, when the receding motion between the wiring head and the substrate is started, the relative translational motion between the wiring head and the substrate is started. During the period from the start of the receding motion to the end of the approaching motion, a given one of the wire conductor sections is drawn out from the wiring head, and the relative translational motion between the wiring head and the substrate is terminated. With this relative translational motion, the wire conductor section is laid on the adhesive layer formed on the substrate surface. At the terminal end of the wire conductor section, the wire conductor is pressed between the wiring head and the adhesive layer formed on the surface of the substrate due to the approaching motion, to be stuck on the surface of the substrate. For the series of wire conductor sections, these conductor sections are disposed and stuck in sequence on the substrate surface. The wire conductor is stuck thereon point by point at respective borders between adjacent pairs of wire conductor sections. The series of relative translational motions is executed by controlling the two-dimensional movement, e.g., of the wiring head or the substrate by a point-to-point control technique. The wiring head and/or the substrate move continuously in appearance, with a short intermission at the border between adjacent wire conductor sections.
Desirably, while a head body of the wiring head and the substrate are disposed to be spaced from each other, a pressing member movably attached to the head body and the adhesive layer formed on the surface of the substrate are caused to contactably close to each other. In this case, the pressing member prevents the wire conductor section already stuck on the surface of the substrate from peeling therefrom.
In the present invention, desirably, the wire conductor supplied to the wiring head is drawn out from the wiring head by the three-dimensional relative movement between the wiring head and the substrate executed in the step (b).
With this desirable method, since the wire conductor is drawn out by the three-dimensional relative movement between the wiring head and the substrate in the step (b), a step of forcedly feeding the wire conductor from the wiring head by using feeding means is not needed.
Desirably, the wiring method of this invention further comprises the steps of (c) providing a second adhesive layer on the wire conductor stuck on the surface of the substrate, and (d) sticking a second wire conductor on the second adhesive layer by causing a three-dimensional relative movement between the substrate and the wiring head adapted to guide the second wire conductor, such that the wiring head relatively moves along the second adhesive layer and the wiring head and the second adhesive layer intermittently come close to each other for point contact.
With this desirable method, wire conductors of the same kind or different kinds can be laid in layers on the substrate.
More desirably, the three-dimensional relative movement between the wiring head and the substrate executed in the step (b) includes a relative translational motion between the wiring head and the substrate which is performed along the adhesive layer, and a relative reciprocal motion between the wiring head and the substrate which is performed in a direction of thickness of the substrate. The relative translational motion is executed in accordance with a first two-dimensional pattern, so that a first wire-conductor pattern corresponding to the first two-dimensional pattern is formed on the surface of the substrate. Further, in the step (c), the second adhesive layer is formed on the first wire-conductor pattern. In the step (d), a relative translational motion between the substrate and the wiring head adapted to guide the second wire conductor is executed in accordance with a second two-dimensional pattern, so that a second wire-conductor pattern corresponding to the second two-dimensional pattern is formed on the second adhesive layer.
With this desirable method, wire conductors of the same kind or different kinds can be laid in layers in the same pattern or different patterns on the substrate.
Desirably, in the step (c), an adhesive sheet, for example, a double-sided adhesive sheet, is stuck on the first wire-conductor pattern to form the second adhesive layer.
This desirable method is convenient in sticking the second adhesive layer at its one side on the adhesive layer provided on the surface of the substrate, with the first wire-conductor pattern interposed therebetween, and in forming the second wire-conductor pattern on the other side of the second adhesive layer.
Desirably, conductors with an insulating coating such as enameled wires (wires with an enamel coating) are used as the wire conductor and the second wire conductor.
With this desirable method, the wire conductor and the second wire conductor or the first wire-conductor pattern and the second wire-conductor pattern can be arranged to extend across each other, without an electrical insulator interposed therebetween. Further, the wire conductors or the wire-conductor patterns can be electrically connected to an external element easily by drawing their ends to the outside, without the need of forming through-holes in the substrate. Further, when the wire conductor or the second wire conductor is to be formed in the shape of a coil, the wire conductor or the second wire conductor can be laid in dense, if necessary, by densely arranging coil sections of the wire conductor one another. Thus, this desirable method is useful, for example, in forming an antenna coil having excellent antenna characteristics.
According to another aspect of the present invention, there is provided a wiring apparatus comprising a supporting mechanism for supporting a substrate having a surface thereof provided with an adhesive layer; a wiring head for guiding a wire conductor, the wiring head being arranged for reciprocal motion between a close position in which the wiring head can be in point contact with the adhesive layer formed on the surface of the substrate and a distant position in which the wiring head is most distant from the adhesive layer; a moving mechanism for causing a relative translational motion between the wiring head and the substrate such that the wiring head relatively moves along the surface of the substrate; and control means for controlling an operation of the moving mechanism.
With the wiring apparatus of the present invention, the wiring head is reciprocated between the close position and the distant position and is caused by the moving mechanism operated under the control of the control means to make a relative translational motion in relation to the substrate so as to relatively move along the surface of the substrate, whereby the wiring head comes close to the adhesive layer formed on the substrate surface each time it assumes the close position. Thus, with use of a relatively simple apparatus arrangement such as to cause the relative translational motion between the substrate and the wiring head that is movable in the directions toward and away from the substrate surface, the wiring head can be intermittently brought close to the adhesive layer for point contact therewith to press the wire conductor between itself and the adhesive layer, whereby the wire conductor can be stuck on the surface of the substrate securely. Further, the wiring apparatus of the present invention has little restriction about the kind of wire conductor, making it possible to lay a desired wire conductor on the substrate.
Desirably, the control means controls the operation of the moving mechanism in accordance with a wiring pattern for laying the wire conductor on the substrate.
With this desirable apparatus, the wiring head is caused by the moving mechanism, operable under the control of the control means, to make the relative translational motion in relation to the substrate in accordance with the wiring pattern, so that the wire conductor guided by the wiring head is laid in the wiring pattern.
In the wiring apparatus of the present invention, desirably, the wiring head has a nozzle for guiding the wire conductor, and when the wiring head is in the close position, a tip of the nozzle is positioned close to the adhesive layer formed on the surface of the substrate for point contact therewith.
With this desirable apparatus, while the wire conductor is being laid, the tip of the nozzle intermittently comes close to the adhesive layer formed on the surface of the substrate for point contact therewith, whereby the wire conductor drawn out from the tip of the nozzle of the wiring head is pressed between the wiring head and the adhesive layer, to be stuck on the surface of the substrate securely.
Desirably, the wiring head has a nozzle having a nozzle hole for guiding the wire conductor, and the nozzle hole extends parallel to the direction of reciprocation of the wiring head.
In this desirable apparatus, while the wiring head recedes from the close position to the distant position, the wire conductor passing through the nozzle hole is drawn out from the wiring head. The relative translational motion between the wiring head and the substrate is associated with the reciprocal motion of the wiring head, for example, as follows: After the wiring head reaches the distant position to cause the wire conductor to be drawn out from the wiring head, the relative translational motion is made between the wiring head and the substrate, so that the wire conductor is disposed on the surface of the substrate. Then, the wiring head and the adhesive layer formed on the surface of the substrate are moved to close to each other, whereby the wire conductor is pressed between the wiring head and the adhesive layer, to be stuck to the surface of the substrate. With this desirable apparatus, the wire conductor can be drawn out from the wiring head and laid securely, without using a device for forcedly feeding the wire conductor from the wiring head.
Desirably, the moving mechanism includes a first table arranged for reciprocal motion relative to the supporting mechanism, and a second table for supporting the wiring head, the second table being arranged for reciprocal motion in a direction perpendicular to an axis along which the first table is reciprocated.
With this desirable aspect, the moving mechanism for causing the relative translational motion of the wiring head in relation to the surface of the substrate can have a simple structure.
Desirably, the wiring head includes a supporting portion mounted to the moving mechanism, a shaft portion supported for reciprocal motion by the supporting portion, a nozzle for guiding the wire conductor, the nozzle being attached to the shaft portion on a side thereof facing the surface of the substrate, an eccentric cam rotatably supported by the supporting portion, and a cam follower attached to the shaft portion on a side thereof remote from the surface of the substrate and disposed in contact with a cam face of the eccentric cam.
With this desirable apparatus, the shaft portion and the nozzle of the wiring head can be reciprocated relative to the substrate surface by rotating the eccentric cam.
More desirably, a plurality of nozzles are detachably attached to the shaft portion of the wiring head. In this case, from among the plurality of nozzles attached to the wiring head, a nozzle suitable for the kind of a wire conductor to be laid on the substrate can be selected for use. Further, the nozzles can be replaced if necessary.
Alternatively, the wiring head includes a head body mounted to the moving mechanism, a nozzle for guiding the wire conductor, the nozzle being supported by the head body for reciprocal motion and for point contact with the adhesive layer formed on the surface of the substrate, a pressing member supported by the head body for reciprocal motion and for point contact with the adhesive layer, a first and second permanent magnets attached to the nozzle and the pressing member, respectively, and having different directions of magnetism, and an electromagnet attached to the head body for electromagnetic interaction with the first and second permanent magnets.
In this desirable apparatus, when an alternating current is supplied to the electromagnet, the nozzle and the pressing member of the wiring head are caused to move in the opposite directions toward and away from the substrate surface due to the electromagnetic interaction between the electromagnet and the first and second permanent magnets. While the wire conductor is being laid, the nozzle and the adhesive layer formed on the substrate surface intermittently come close to each other for point contact to press the wire conductor therebetween, whereby the wire conductor is stuck on the surface of the substrate securely. Further, as the nozzle and the adhesive layer are moved away from each other, the pressing member and the adhesive layer are moved close to each other, thereby pressing the wire conductor disposed on the adhesive layer therebetween, so as to prevent the wire conductor having been stuck on the substrate surface from separating therefrom. Desirably, the nozzle is detachably attached to the head body and can be replaced with another nozzle, depending on the kind of a wire conductor to be laid.
According to another aspect of the present invention, there is provided an IC card manufacturing method comprising the steps of (a) sticking an electrical component on an adhesive sheet; (b) laying a wire conductor on the adhesive sheet by causing a relative movement between the adhesive sheet and a wiring head adapted to guide the wire conductor such that the wiring head relatively moves along a surface of the adhesive sheet and the wiring head and the adhesive sheet intermittently come close to each other for point contact; (c) electrically connecting each end of the wire conductor to the electrical component; and (d) sticking the adhesive sheet and a card substrate together.
In the IC card manufacturing method of the present invention, when the wire conductor is to be laid on the card substrate, neither the card substrate nor the wire conductor needs to be heated. Thus, increase of cost due to the use of heating means, severe control of heating temperature, and fatigue breakage of the wire conductor due to heating by ultrasonic vibration can be avoided, therefore, IC cards can be manufactured easily, with high reliability and at low cost.
In the IC card manufacturing method of the present invention, desirably, in the step (d), a first card substrate is stuck on that first surface of the adhesive sheet on which the electrical component is stuck, and a second card substrate is stuck on a second surface of the adhesive sheet.
With this desirable method, a protection can be provided for the electrical component stuck on and the wire conductor laid on the adhesive sheet by sandwiching the electrical component and the wire conductor between the first and second card substrates.
More desirably, in the step (a), the electrical component is stuck on an exposed first adhesive surface of a double-sided adhesive insulating sheet having a second adhesive surface thereof provided with a separating sheet. In the step (b), the wire conductor is laid on the exposed first adhesive surface of the double-sided adhesive sheet. In the step (d), the first card substrate is stuck on the exposed first adhesive surface of the double-sided adhesive sheet, the separating sheet is separated from the second adhesive surface of the double-sided adhesive sheet, and then the second card substrate is stuck on the second adhesive surface.
With this desirable method, the first and second card substrates can be stuck on the double-sided adhesive sheet, making use of the adhesiveness thereof. Thus, the sticking step (b) can be carried out easily.
In the IC card manufacturing method of the present invention, desirably, in the step (b), an antenna coil is formed on the adhesive sheet by laying the wire conductor in a predetermined pattern on the adhesive sheet.
In this desirable method, the antenna coil is formed of the wire conductor laid on the adhesive sheet, through a relative movement between the wiring head and the adhesive sheet. The laying step has little restriction about the kind of wire conductor to be laid and the relative movement between the wiring head and the adhesive sheet for the laying step can be controlled precisely. Thus, for example, by using an copper wire with an enamel coating as the wire conductor, coil sections of the wire conductor, each of which has a circular or rectangular shape and which are disposed as a whole into a spiral form, are arranged at a high density while ensuring the insulation between adjacent coil sections, whereby the antenna characteristics of an antenna coil can be improved, and therefore, an IC card accommodating therein an antenna coil of desired antenna characteristics and adapted for wireless communication can be provided.
Desirably, in the step (a), at least one of a semiconductor chip, a chip resistor, a chip capacitor and a terminal is stuck on the adhesive sheet as the electrical component.
With this desirable method, by sticking desired electrical components on the adhesive sheet, an IC card having desired capability can be manufactured.
Desirably, in the step (a), a plurality of electrical components are stuck on the adhesive sheet; in the step (b), at least one electric wiring pattern is formed on the adhesive sheet by laying the wire conductor in a predetermined pattern on the adhesive sheet; and in the step (c), the electric wiring pattern is electrically connected with relevant ones of the plurality of electrical components.
With this desirable aspect, the electrical components can be connected via the electric wiring pattern formed of the wire conductor. Thus, the IC card can be manufactured easily.